The invention relates to a sewing device for forming seams on similar workpieces, but of different length. The device is provided with two substantially symmetrically formed workpiece clamping holders adjustable relative to each other according to the length of the workpiece, a master cam comprising two symmetrically formed external segments which are connected by a bridging rail for forming a continued edge. Along the profile of the cam edge on the master cam rolls a driven magnetic roller which controls the sewing machine, and a device for the positioning control and for inserting the workpiece cuts to be sewn into the workpiece clamping holders and simultaneously removing the finished workpieces therefrom.
U.S. Pat. No. 3,216,380 discloses an automatic operating sewing machine for sewing of like patterns of different lengths, which comprises a fabric holder adjustable in a predetermined direction and in accordance with the desired shape of sewing, for effecting the movements of the fabric holders, a pattern including two end positions and a bridging intermediate portion which is adjustably movable along a straight line relative to each other by means of a threaded spindle operated by a hand wheel. However variation of the workpiece sizes requires a manual resetting of one of the two fabric holder parts.
There is further disclosed in U.S. Pat. No. 3,407,759 a sewing device which is provided with a rotary table and clamping means for receiving workpiece cuts to be processed and successively fed into the effective range of tooling machines, e.g. a sewing machine and a cutting machine due to the rotation of the rotatary table. The table is provided with radially disposed segments, each carrying templates for engaging with a magnetic roller which is coaxial with the needle of the sewing machine and the clamping means for a right and a left half of two neighbouring workpieces. These segments are radially displaceable as per a scale by means of a control adjusting device.
However, the aforesaid known devices do not include means for inserting of previously aligned workpiece cuts into the opened workpiece clamping means, quick-adjusting means for sewing similar workpiece cuts of different length, and for simultaneously removing of sewn workpieces out of the workpiece clamping means.
It is an object of this invention to provide an automatically operating sewing device of the above mentioned kind with central quick-adjusting means for the changeover to any different workpiece sizes or dimensions.
It is a further object of the invention to provide said sewing device with means for inserting workpiece cuts to be sewn into the opened workpiece clamping holders and simultaneously removing of a sewn workpiece out of the same holder.
Other objects and advantages of the present invention will become apparent from the following description in conjunction with the attached drawings which illustrate a preferred embodiment.